Pulled the latest source from github, installed the dependencies except for sky (haven't looked into it yet), made appropriate modifications to configure,sh, and tried to build with qtmake from command line and qtcreator graphically. I'm building with qt5. I have the package qt5-declarative installed but I'm getting an Unknown module(s) in QT: declarative error.

I've never done any dev with qt; someone more knowledgeable about it would have better luck I imagine.

I also tried building MotionBox on ArchLinux few weeks ago, but I didn't continue because it uses qt4. I don't want to install qt4 on my system, I have only qt5 installed. And porting MB to qt5 could potentially be too much work.

I'm looking at the configure,sh for Sky and I see why declarative wasn't found when I tried building MotionBox with qt5. Arch Linux has a qt5-declarative package, but it does not have the folder names that are being copied in the script.

I haven't gotten around to looking into them yet, if anyone else wants to poke around in the meantime though those compiler errors should point you towards whatever needs to be changed to build on linux

From googling the error it looks like the problem is that it is trying to compile without -fPIC. I've tried adding it with QMAKE_CFLAGS and QMAKE_CXXFLAGS in the SkTorrent,pro but it seems to completely ignore it... I know that my changes are visible however, as I am able to change the name of libraries to link to when I edit the LIBS :/

That's why I'm linking with the lib using the "-static" prefix. I guess linux libtorrent libraries are dynamic, did you try removing the "-static" prefix ?

Good call, didn't think of that. I now have Sky built on Linux :)
I'll clean up my changes to the .pro files so that it doesn't mess with the Windows build, rebase my commits, and submit a pull request later tonight!

Also, I'm interested in having it work on ubuntu, possibly with an installer. I'm currently using the Qt Installer Framework.

On ubuntu the standard way to install a piece of software is with a deb package. Most projects that provide linux builds provide their software in .deb, .rpm, and source (.tar.gz) formats. deb and rpm packages cover the major distros; other distros (such as Arch) normally rely on the community of users to maintain special packages that either build from source or extract the files from a deb/rpm.

I'm not familiar with creating deb packages (nor do I really want to maintain packages for platforms I don't use), so I'm afraid you'll need to find someone else to help with the deb and rpm packages. I'm happy to help get the source building on Linux and maintaining packages for Arch though :)